To date, applications in which ion sources have been employed include devices for implanting ions into semiconductor substrates, ion-beam etching devices, and thin-film coating devices for various components.
As evaporation sources for evaporating solids such as metals, heating schemes and electron beam injection schemes are known, and for the ionization of evaporation gases, a technique whereby electrons are collided with vaporized precursor gases to ionize the gases is known.
Among techniques that employ an electron beam injection scheme for the evaporation source, a precedent is disclosed in Patent Document 1, in which electron collision-ionization in a vapor from an electron beam injected on an evaporation region and from the secondary electrons therein gives rise to a plasma. Utilizing the electron beam injected on the evaporation region to give rise to the electric ionization action requires raising the gas pressure in the evaporation region and lowering the speed of the injecting electron beam to enlarge the cross-sectional area of the electron collisions. Therein, if its energy is set low the electron beam collides with the precursor gas on the path to the evaporation region, which degrades the efficiency of evaporation by the electron beam that arrives at the evaporation region. Meanwhile, a problem with setting the vacuum level low has been that it gives rise to electric discharge in the electron gun, such that the electron beam cannot form.
On account of the foregoing, an awareness that it is difficult to cause electrons for evaporation and electrons for ionization to act simultaneously in ambients of identical vacuum level has been held to date. Furthermore, an awareness that furnishing electric discharge electrodes in proximity to the evaporation source exerts an influence on the electric field for deflecting the electron beam introduced into the evaporation region, spoiling the directivity of the electron beam, has been held to date.
In order to resolve the above-described problems, the inventor involved with the present invention carried out discoveries with solid-state ion sources, disclosing them in Patent Document 2.
With the just-noted solid-state ion sources, the interspace between the precursor evaporation chamber and the plasma chamber is compartmentalized with a partitioning wall having a precursor-gas diffusion port for diffusing the vapor (precursor gas) into the plasma chamber, and at the same time an exhaustion port is provided on the electron beam generating section of the electron beam evaporator, making it so that even with the gas pressure in the precursor evaporation chamber growing high due to exhaustion being carried out, electric discharge in the electron beam generating section will not occur.